Jurassic is not yet production ready
What's supported
All ECMAScript 3 functionality
Partial ECMAScript 5 functionality
Native JSON support
All ECMAScript 5 built-in library functions (except bind)
Known issues
Attempting to return from a finally statement fails
eval is not scoped correctly
The arguments object has some issues
Line numbers and stack traces are not available
Global RegExp properties are not supported (e.g. RegExp.$1)
Calling toString() on functions does not return the source code for the function
ECMAScript 5 strict mode is not supported
Read more: Codeplex